Innovia Shrinkfilms GmbH, a specialty film manufacturer and a division of CCL Industries Inc. and the world’s largest producer of labels, recently solved an out-of-tolerance issue through the simple expedient of switching dies.
To supply the fast-growing shrink sleeve segment of the label market, Innovia produces transparent film that is subsequently printed on the inside surface, slipped over a container, and made to conform to the container surface by means of heat shrinking.
The company was processing a polystyrene blend into monoaxially-oriented film on one of its cast film lines but noticed the product from this line was often out of tolerance.
Switching to a die from Nordson Corporation improved tolerances by 30% as well as reducing startup times, the company said.
The new EDI Autoflex VI-RE H40 unit is an automatic die, that uses data from a computerized downstream gauging system to adjust the transverse thickness profile by making changes to the flexible upper lip of the die. According to Giuseppe Ronzoni, Innovia plant manager, the result is a faster and more accurate automatic control of the flexible lip and faster startups than before.
The flexible lip of an Autoflex die is made up of thermally-actuated adjuster blocks that expand or contract to adjust the lip gap in areas of the film that are thicker or thinner than the target dimension.
In addition, the lip land—the lip surface just before the die exit- can be made longer or shorter to optimize product thickness, flatness, and surface finish
At startups, the rapid gauge profile adjustment provided by the Autoflex system reduces the time before saleable product is produced. Also helping to shorten startups is the design of the flow channel, or manifold, inside the die.
“The greater uniformity of the film produced with the EDI die reduces the potential for gauge bands on the product roll,” said Ronzoni. “This leads to less stretching of the final product and better printing results.”